The present invention relates to a dielectric waveguide in a multi-layer printed circuit board (PCB).
Computing systems rely on high speed buses to transmit data between different components—e.g., processors, memory, accelerators, I/O devices, graphics cards, and the like. Differential signaling is primarily used for short high speed buses. In this technique, each signal line includes two wires which transmit opposite polarity signals. A receiver coupled to the two wires calculates the voltage difference between the wires to determine the data bit being transmitted. Using differential signaling rather than a single wire for each data bit significantly reduces the impact of noise and radiated emissions on the transmitted signal. However, as data speeds increase (e.g., greater than 25 Gb/s), the lengths at which a bus can effectively use differential signaling are reduced.
Fiber optics is another technique for transmitting data between computing devices at high speeds. Fiber optics can transmit signals at speeds above 100 Gb/s for much farther distances than a bus that uses differential signal. However, optical transmitters and receivers are expensive and require more space relative to the drivers and receivers used to perform differential signaling.